For some time various products have been packaged in packages which comprise paper alone or paper in combination with a thermoplastic film. Such packaging has typically included a plurality of paper layers, with a relatively thin, flexible plastic film adhered to the inside paper layer, the film serving as a moisture and grease barrier. The paper provides the package with an exterior surface which is highly printable, as well as a stiffness which provides the packaging article, which is, for example, a gusseted bag, with an ability to be self-supporting and to provide the package with overall aesthetic qualities which consumers perceive as being desirable. Such paper packaging has been used in a variety of applications, particularly gusseted bags which are used in the packaging of dry granular material such as pet food, livestock feed, sugar, coffee, cookies, cereals, baking products such as cake mixes, crackers, chips, powdered milk, charcoal, cement, fertilizer, lime, pesticides, etc. The packaging can also be used to package cheese, in grated, ground, and/or block form.
More recently, paper-free plastic film packaging materials have been used for the packaging of a such products as pet food, etc. In order to obtain a desirable performance level, i.e., in terms of impact strength and toughness, such packaging films have contained relatively large quantities of polymers which are recognized for their toughness and impact resistance, such as polyamide, polyester, and polyacrylonitrile. However, these polymers are also relatively expensive. It would be desirable if a comparably tough, impact-resistant package could be made from less expensive polymers. Moreover, it would also be desirable to provide packaging which provides a high O.sub.2 -barrier layer to increase the shelf-life of the product. In addition, in such plastic packaging, particularly in the packaging of hard, granular bulk products such as dry pet food, it has been found that "dimples" tend to form in the plastic, thereby creating a rough, dimpled appearance in the outside of the package. It would be desirable to provide packaging which avoids this "dimpling" effect. Finally, it would be desirable to provide such packaging which is also relatively stiff, e.g., capable of providing a self-supporting gusseted bag.
In the case of the packaging of food in paper packaging, particularly pet food, it has heretofore been desirable to mix antioxidant into the food product; otherwise the food tends to lose metabolizable energy, exhibit decreased acceptability, including undesirable odors and flavors, protein degradation, and the development of health hazards in the consuming animal. Thus, without antioxidant present, food packaged in paper packaging exhibits reduced shelf-life and/or reduced product quality. It would be desirable to provide a type of packaging which requires less antioxidant, or even no antioxidant, to be mixed with a food product within the package, without the detrimental effects associated with the oxidation of the food product. In this manner, the expense of providing the antioxidant as well as the mixing of the antioxidant with the food product, are both reduced or avoided, while maintaining a good shelf life for the packaged food product.